Sometimes the desire for good health is overwhelmed by the simple fear of bad health. The middle-aged man, for instance, conscience-stricken by a lifetime of bacon-and-eggs breakfasts, wakes up suddenly and wants to get a thorough heart scan. What could be the problem?

Plenty, as it turns out. We could all be getting entirely too much radiation blasted into our bodies in our quest to prevent future diseases. According to a leading cardiologist, it’s the ticking time bomb of our present health-care system.

In November, the U.S. Preventive Services Task Force recommended that women wait until age 50 to begin regular mammography tests, and then to get them every two years, based, in part, on potential harms from over-screenings. Several groups, including the American Cancer Society, responded swiftly that this would result in women dying unnecessarily as they delayed screenings.

But there are several watchdog groups now questioning our national overindulgence in radiation-based testing. The radiation from mammographies, some studies suggest, may even cause more cancer than the screenings prevent. Because the answer is not definitive, any report on this question comes freighted with qualifiers: The exact dangers are not clear. It remains to be seen.

Countering CT Scans

Existing reports, however, are startling. The riskiest agent at hand is actually the CT scan (short for computed tomography, also called the “cat scan”). A typical radiation dose from a CT scan is 600 times more powerful than the average chest x-ray. And CT scans have become ubiquitous—more than 72 million are now administered annually, compared to three million in 1980.

The average patient might never be advised about the dangers of radiation, or need to answer questions about past radiation treatments. If the insurance company will pay, hospitals and clinics are not likely to talk patients out of it. Indeed, there is some evidence that cash-strapped hospitals derive a satisfying amount of profit from these expensive tests. Hospitals have also been stepping up the use of expensive MRIs, but since those tests use radio and magnetic waves (or “magnetic resonance imaging”) and not radiation, there is not the danger now associated with CT scans.

The CT scan appears to be a fantastic, noninvasive diagnostic tool, and there is no question it works. A few years ago, Oprah Winfrey was touting the whole-body CT scan as the forefront of defensive medicine. But now The New England Journal of Medicine has said that a third of CT scans are unnecessary.

Further, the amount of radiation emitted in CT scans varies enormously. Three hospitals in the Los Angeles area, including the famed Cedar-Sinai Medical Center, are being investigated by the Food and Drug Administration after reports that they used excess radiation on more than 250 patients.

In that investigation, incidents of hair loss and skin redness were the giveaways. But researchers in general believe that it takes twenty years for a radiation-induced cancer to develop. The gradualness of the process is one reason that researchers are alarmed at the CT scans administered to children, given that their cells are rapidly dividing and are thus highly susceptible to the torments of irradiation. Diagnosticians have the ability to administer a low-dose test on children, but it is not always done.

The Cancer Connection

In December, two damning reports were issued in the Archives of Internal Medicine, in which a research team of doctors lambasted the casual treatments of children and the overuse of multiple CT scans on a single patient. One study, headed by Dr. Amy Berrington de Gonzãlez of the National Cancer Institute, looked at the 72 million scans given in 2007 and projected that there will be 29,000 cancers from that year alone as a result, excluding those scans conducted after a cancer diagnosis or performed at the end of life. “These cancers will appear in the next 20 to 30 years,” said the report, “and at a 50% mortality rate, will cause approximately 15,000 deaths annually.”

It is studies like this that are informing the new guidelines on mammographies. Already, women have had to weigh the costs and benefits of early screenings, asking: Will the mammography lead to an unnecessary biopsy? What’s the family history? Now they must add considerations about the potential risks of radiation exposure.

“Physicians and their patients cannot be complacent about the hazards of radiation or we risk creating a public-health time bomb,” says Dr. Rita Redberg, cardiologist at University of California-San Francisco Medical Center and Archives editor. “To avoid unnecessarily increasing cancer incidence in future years, every clinician must carefully assess the expected benefits of each CT scan and fully inform his or her patients of the known risks of radiation.”

Until the health industry standardizes its practices, patients need to keep good records of family radiation treatments and consult with doctors on alternatives.